JP6413077B2 - Host device, slave device, interface semiconductor device, and removable system - Google Patents

Description

  The present disclosure relates to a host device, a slave device, an interface semiconductor device, and a removable system.

  In recent years, slave devices such as a card-shaped SD card and a memory stick, which have a large-capacity nonvolatile memory element such as a flash memory and can process data at high speed, have spread in the market. It is used in personal computers, smartphones, digital cameras, audio players, car navigation systems, and the like, which are host devices that can use slave devices.

  For example, Patent Document 1 discloses a technique for selecting an operating voltage from a plurality of interface voltages in a communication system using a host device and a slave device.

International Publication No. 2009/107400

  In a communication system using a host device and a slave device, it is effective to reduce the interface voltage in order to improve the interface processing speed. Furthermore, with the recent miniaturization of semiconductor processes, there is an increasing demand for introducing semiconductor devices limited to a lower interface voltage. On the other hand, there is a demand for maintaining interface compatibility so that existing interfaces that are prevalent in the market can be used continuously.

  When trying to satisfy these simultaneously, there is a possibility that a slave device with a new interface corresponding to an interface voltage relatively lower than that of the existing interface is erroneously attached to a host device with an existing interface. Similarly, a slave device with an existing interface may be erroneously attached to a host device with a new interface corresponding to an interface voltage that is relatively lower than the existing one. Then, there is a possibility that the new interface-side device is destroyed by the relatively high interface voltage of the existing interface-side device.

  The present disclosure has been made in view of the above-described problems. A host device, a slave device, an interface semiconductor device, and a removable device that can be used safely even when the interface compatibility is reduced and the interface voltage is reduced. Provide a system.

  The present disclosure can be mechanically connected to both the first slave device corresponding to the first interface voltage and the second slave device corresponding to the second interface voltage lower than the first interface voltage. After notifying the interface unit and the slave device attached to the interface unit of the request signal, the response signal notified from the slave device in response to the request signal is a response signal from the second slave device. If it is determined, while continuing the initialization operation with the second interface voltage, while determining that the response signal notified from the slave device in response to the request signal is not a response signal from the second slave device, And a control unit that regulates the initialization operation.

  In addition, the present disclosure is mechanically connected to both the first host device corresponding to the first interface voltage and the second host device corresponding to the second interface voltage lower than the first interface voltage. When the voltage of the power source supplied from the interface unit and the host device mechanically connected to the interface unit is detected and the detected voltage corresponds to the first interface voltage, the initialization operation is not performed. When the detected voltage corresponds to the second interface voltage, the slave device includes a control unit that performs an initialization operation.

  In addition, the present disclosure is mechanically connected to both the first host device corresponding to the first interface voltage and the second host device corresponding to the second interface voltage lower than the first interface voltage. If the detected interface voltage and the voltage of the power source supplied from the host device mechanically connected to the interface unit are detected and the detected voltage corresponds to the first interface voltage, the first initialization operation is performed. On the other hand, when the detected voltage corresponds to the second interface voltage, the slave device includes a control unit that performs a second initialization operation different from the first initialization operation.

  In addition, the present disclosure mechanically connects both the first slave device corresponding to the first interface voltage and the second slave device corresponding to the second interface voltage lower than the first interface voltage. After the request signal is notified to the possible interface circuit and the slave device mounted on the interface unit, the response signal notified from the slave device in response to the request signal is the response signal from the second slave device. If it is determined that there is, the initialization operation by the second interface voltage is continued, while it is determined that the response signal notified from the slave device in response to the request signal is not the response signal from the second slave device In this case, the interface semiconductor device is formed with a control circuit that regulates the initialization operation.

  In addition, the present disclosure is a removable system formed of a host device and a slave device that is detachable from the host device. The host device includes a first slave device corresponding to a first interface voltage, a first slave device, The interface unit which can be mechanically connected to both of the second slave device corresponding to the second interface voltage lower than the interface voltage of 1 and the slave unit attached to the interface unit are notified of the request signal. Thereafter, when it is determined that the response signal notified from the slave device in response to the request signal is a response signal from the second slave device, the initialization operation by the second interface voltage is continued, while the request signal The response signal notified from the slave device in response to is determined not to be the response signal from the second slave device. If it, a control unit for regulating the initialization operation, equipped with a removable system.

  The present disclosure can provide a host device, a slave device, an interface semiconductor device, and a removable system that can be used safely even if the interface voltage is reduced while maintaining interface compatibility.

Block diagram showing the configuration of a conventional host device and a removable system composed of slave devices The figure explaining the initialization routine of a non-UHS slave device and a UHS-I slave device Diagram explaining details of I / F condition check command and response, initialization command and response The block diagram which showed the structure of the removable system which consists of LV host apparatus and LV slave apparatus concerning Embodiment 1 of this invention The figure explaining the initialization routine of the LV slave device according to the first embodiment of the present invention The figure explaining the detail of I / F condition check command and response, initialization command, and response concerning Embodiment 1 of this invention A block diagram showing a configuration of a removable system comprising an LV host device and a DM slave device according to the second embodiment of the present invention. The block diagram which showed the structure of the removable system which consists of a host apparatus and DM slave apparatus concerning Embodiment 3 of this invention. The block diagram which showed the structure of the removable system which consists of LV host apparatus and UHS-I slave apparatus concerning Embodiment 4 of this invention The figure explaining the initialization routine of the UHS-I slave apparatus concerning Embodiment 4 of this invention The block diagram which showed the structure of the removable system which consists of LV host apparatus and UHS-I slave apparatus concerning Embodiment 5 of this invention The figure explaining the initialization routine of the UHS-I slave apparatus concerning Embodiment 5 of this invention FIG. 7 is a block diagram showing a configuration of a removable system including a conventional host device and an LV slave device according to a sixth embodiment of the present invention. The figure explaining the initialization routine of the LV slave device according to the sixth embodiment of the present invention The figure explaining other embodiment about an I / F condition check command and a response, an initialization command, and a response The figure explaining the case where the value of the received LV check area is subjected to a predetermined conversion and returned in the initialization routine of the LV slave device

  Hereinafter, embodiments will be described in detail with reference to the drawings as appropriate. However, more detailed description than necessary may be omitted. For example, detailed descriptions of already well-known matters and repeated descriptions for substantially the same configuration may be omitted. This is to avoid the following description from becoming unnecessarily redundant and to facilitate understanding by those skilled in the art.

The inventor (s) provides the accompanying drawings and the following description in order for those skilled in the art to fully understand the present disclosure, and is intended to limit the subject matter described in the claims. Not what you want.
[1. Issues to be solved by the removable system according to the present disclosure]
First, problems to be solved by the removable system according to the present disclosure will be described with reference to FIGS. 1 to 3.

[1-1. Configuration of Conventional Host Device and Conventional Slave Device]
FIG. 1 is a block diagram illustrating a configuration of a removable system 10 in which a conventional slave device 120 that can be inserted and removed is connected to a conventional host device 100. As shown in FIG. 1, the host device 100 includes a power supply unit 101, an I / F (interface) signal regulator 102, and an I / F semiconductor chip 103. The I / F semiconductor chip 103 includes a host device I / F unit 104 and an I / F control unit 105.

  The host device 100 and the slave device 120 are mechanically connected. The host device 100 is electrically connected to the slave device 120 via the power supply line 110.

  The slave device 120 includes an I / F signal regulator 121, an I / F semiconductor chip 122, a BE (back end) regulator 125, and a back end module 126. The back end module 126 refers to a recording medium such as a flash memory or a device such as a wireless communication module. The I / F semiconductor chip 122 includes a slave device I / F unit 123 and an I / F control unit 124.

  The host device I / F unit 104 and the slave device I / F unit 123 perform signal communication via a CLK (clock) line 111, a CMD (command) line 112, and a DAT (data) line 113.

  FIG. 2 is a diagram for explaining an initialization routine after power-on in the conventional host device 100 and slave device 120.

  The conventional slave device 100 includes a non-UHS slave device and a UHS-I slave device. The non-UHS slave device is a slave device in which the signal voltage of the CLK line 111, the CMD line 112, and the DAT line 113 is a 3.3V high voltage signal (hereinafter referred to as a 3.3V signal). The UHS-I slave device is a slave device that uses a 3.3V signal immediately after power-on and switches to a 1.8V low voltage signal (hereinafter referred to as a 1.8V signal). The host device 100 identifies whether the attached slave device is a non-UHS slave device or a UHS-I slave device based on the UHS-I support flag. Note that the power supply voltage supplied to the non-UHS slave device and the UHS-I slave device via the power supply line is a 3.3V high voltage power supply (hereinafter referred to as 3.3V power supply).

  FIG. 3 is a diagram illustrating details of commands and responses in the initialization routine.

[1-2. Detailed operation of conventional host device and slave device]
The operation when the conventional slave device 120 is attached to the conventional host device 100 will be described below with reference to FIGS.

  At the time of power activation, 3.3 V power is supplied from the power supply unit 101 of the host device 100 to the slave device 120 via the I / F signal regulator 102 and the power line 110. The I / F signal regulator 102 is a device that appropriately converts the voltage of the supplied power supply according to an instruction from the I / F control unit 105 and outputs the converted voltage. Then, the I / F signal regulator 102 supplies 3.3V power as it is to the I / F semiconductor chip 103 and the host device I / F unit 104 immediately after the power is turned on. The I / F semiconductor chip 103 supplies the supplied 3.3V power to all modules arranged in the I / F semiconductor chip 103 so that each module can be operated. The 3.3 V power supplied to the host device I / F unit 104 is the source of the 3.3 V signal on the CLK line 111, the CMD line 112, and the DAT line 113 output from the host device I / F unit 104. .

  On the other hand, the 3.3V power supplied to the slave device 120 via the power supply line 110 is supplied to the I / F signal regulator 121 and the BE regulator 125. The I / F signal regulator 121 is a device that appropriately converts the voltage of the supplied power supply according to an instruction from the I / F control unit 124 and outputs it. Immediately after the power supply from the host device 100 is supplied, the input power supply Is output as is and supplied to the I / F semiconductor chip 122 and the slave device I / F unit 122. The I / F semiconductor chip 122 supplies the supplied 3.3V power source to all modules arranged in the I / F semiconductor chip 122 so that each module can be operated. The 3.3V power supplied to the slave device I / F unit 123 becomes a source of the 3.3V signal of the CMD line 112 and the DAT line 113 output from the slave device I / F unit 123. Further, the BE regulator 125 converts the supplied 3.3V power source into a voltage necessary for driving the back-end module 126 and supplies the power.

  The host device I / F unit 104 of the host device 100 is connected to the slave device I / F unit 123 of the slave device 120 through the CLK line 111, the CMD line 112, and the four DAT lines 113. On the CLK line 111, a single-ended clock signal is transmitted from the host device 100 to the slave device 120. A command for the host device 100 to control the slave device 120 and a response corresponding to each command are transmitted to the CMD line 112 by a single end method. Basically, the host device 100 transmits a command to the slave device 120, and the response is transmitted from the slave device 120 to the host device 100. Therefore, the CMD line 112 is bidirectional communication.

  On the other hand, the DAT line 113 is a signal line that mainly transmits data contents such as still images and texts at high speed, and is composed of four signal lines. The configuration of the signal line is the same as that of the CMD line 112.

  After power-on, the host device I / F unit 104 generates a 3.3 V signal single-ended clock from the 3.3 V (high voltage) power source supplied from the I / F signal regulator 102, and generates this clock. The data is supplied to the slave device I / F unit 122. The initial state of the signal direction of the CMD line 112 and the DAT line 113 is in the direction from the host device 100 to the slave device 120. That is, in the initial state, the terminal on the host device I / F unit 104 side is in the output state, and the terminal on the slave device I / F unit 123 side is in the input state, that is, the release (high impedance) state. Although not shown, each signal line of the CMD line 112 and the DAT line 113 is connected to the output of the I / F signal regulator 102 via a pull-up resistor, so that the host device I / F unit in the output state When the terminal 104 is not driven to the low level (0) or the high level (1), the terminal transits to the high level (1) by the 3.3V power supply.

  After completing the power activation, the host device 100 enters an initialization routine for confirming and initializing the characteristics of the attached slave device 120. The host device I / F unit 104 sends an I / F condition check command 201a, which is a command for checking the I / F condition (for example, the corresponding power supply voltage) of the slave device that is initially mounted, to the I / F control unit 105. And transmitted to the slave device I / F unit 123 via the CMD line 112. The above-mentioned I / F condition check command 201a includes a Reserved area as shown in FIG. 3, and the I / F control unit 105 sets all the values to 0 as described above.

  The I / F condition check command 201 a is transmitted to the I / F control unit 124 via the slave device I / F unit 123. The I / F control unit 124 interprets the content of the command, generates a corresponding response 201b (see FIG. 3 for details), and returns it to the host device 100 via the CMD line 112.

  Subsequently, the host device 100 transmits an initialization command 202 a to the slave device 120. In addition to the reserved area, the initialization command 202a includes a UHS-I support confirmation bit for confirming whether or not a UHS-I device is attached. A host device that supports UHS-I uses the UHS-I. Set the support confirmation bit to 1.

  The I / F control unit 124 of the slave device 120 that has received the initialization command 202 a returns a response 202 b including at least a UHS-I support flag and an initialization completion flag, and starts initialization of the back-end module 126. The slave device 120 can accept the initialization command 202a many times until the back-end module 126 shifts to the next process during initialization and after completion of initialization. If the initialization is in progress, 0 is set in the initialization completion flag of the response 202b. If the initialization is completed, 1 is set. When the UHS-I support confirmation bit of the initialization command 202a is set to 1, the UHS-I support flag of the non-UHS slave device is 0, and the UHS-I support flag of the UHS-I slave device is 1 It becomes.

  When the host device 100 receives the response 202b including the initialization completion flag 1 within a predetermined time after issuing the first initialization command 202a, the host device 100 determines that the initialization of the slave device 120 is completed.

  When the UHS-I support flag in the response 202b is set to 0, the host device 100 determines that the attached slave device 120 is a non-UHS slave device. In this case, various commands 203a and their corresponding responses 203b exchanged between the host device 100 and the slave device 120 are transmitted by 3.3V signals. A clock transmitted through the CLK line 111 and data via the DAT line 113 are also transmitted as a 3.3V signal.

  A communication mode as shown in FIG. 2A is referred to as a non-UHS mode.

On the other hand, when the UHS-I support flag of the response 202b is set to 1, the host device 100 determines that the attached slave device 120 is a UHS-I slave device.
In this case, the host device 100 transmits a voltage switching command 211a to the slave device 120. The I / F control unit 124 that has received the power supply switching command 211a returns a corresponding response 211b, sets all the terminals of the slave device I / F unit 123 to the input state, and then sends the response to the I / F signal regulator 121. The output is instructed to be a 1.8V low voltage power supply (hereinafter referred to as a 1.8V power supply).

  When the I / F control unit 105 receives the response 211b from the slave device 120, the host device 100 drives all the CLK line 111, the CMD line 112, and the DAT line 113 to the low level (0), and the I / F Instructs the signal regulator 102 to use the output as a 1.8V power supply.

  Thereafter, a clock based on a 1.8V signal is transmitted to the CLK line 111, and after a predetermined procedure, the host device 100 and the slave device 120 use the CMD line 112 to execute various commands 203a and corresponding responses 203b based on the 1.8V signal. Exchange. Data transmission via the DAT line 113 is also based on a 1.8V signal.

  A communication mode as shown in FIG. 2B is referred to as a UHS-I mode.

  The details of the signal voltage switching sequence accompanying the voltage switching command 211a are disclosed in Patent Document 1.

  Recently, due to miniaturization of semiconductor processes, it has become difficult for a semiconductor chip particularly for a host device to cope with a high voltage signal of 3.3V. Therefore, for example, it is desired to introduce an I / F semiconductor chip whose input / output is limited to a low voltage signal of 1.8V or less into the host device of the removable system.

  On the other hand, many removable systems such as SD cards (slave devices) and host devices compatible with SD cards are already widely used, and new form factors such as signal line layout and slave device size and shape have been introduced. Replacing with is not preferable in terms of design and manufacture for both the host device and the slave device, and it is preferable that the conventional interface can be used continuously.

  However, when the input / output of the I / F semiconductor chip 103 is limited to the low voltage signal (1.8 V) in the host device 100 shown in FIG. 1, the following problems occur.

  At this time, the output of the I / F signal regulator 102 of the host device 100 can be a 1.8V power supply instead of a 3.3V power supply after the power is turned on. On the other hand, when the 3.3V power supply compatible slave device 120, on which many products are already on the market, is mounted on the 1.8V power supply compatible host device 100, the 3.3V power supply is slaved via the power supply line 110. Supplied to the device 120. As described above, in the slave device 120, the output of the I / F signal regulator 121 immediately after the power supply is activated is the 3.3V power supply. Therefore, the slave device 120 returns a response 201b of the I / F condition check command 201a received for the first time after the power is turned on to the host device 100 with a 3.3V signal. As a result, a 3.3 V signal is input to the I / F semiconductor chip 103 (input / output is a low-voltage signal) of the host device 100, which causes a problem that the I / F semiconductor chip 103 is destroyed.

The inventor has recognized this problem in the process of developing a removable system and has come up with a solution. The details of the solution will be specifically described below. In the following description, the first embodiment will be described as an example in which the technical idea of the solving means is embodied.
[2. Configuration and Operation of Removable System According to First Embodiment]
[2-1. Constitution]
FIG. 4 is a block diagram illustrating the configuration of the removable system 20 to which the LV host device 400 and the LV slave device 420 of the present invention are connected. As shown in FIG. 4, the LV host device 400 includes a low voltage power supply unit 401 and a low voltage I / F semiconductor chip 402. The low voltage I / F semiconductor chip 402 includes a host device I / F unit 403 and an I / F control unit 404.

  The LV host device 400 and the LV slave device 420 are mechanically connected. Further, the LV host device 400 is electrically connected to the LV slave device 420 via the power supply line 110 in the same manner as the removable system 10 described in FIG.

  The LV slave device 420 includes an I / F signal regulator 421, a power supply voltage detection unit 422, an I / F semiconductor chip 423, a BE regulator 426, and a back end module 427. The I / F semiconductor chip 423 includes a slave device I / F unit 424 and an I / F control unit 425.

  The host device I / F unit 403 and the slave device I / F unit 424 have a CLK (clock) line 111, a CMD (command) line 112, and a DAT (data) line 113, as in the removable system 10 described in FIG. Signal communication is performed via

  FIG. 5 is a diagram for explaining an initialization routine after power activation in the LV host device 400 and the LV slave device 420.

  FIG. 6 is a diagram for explaining details of commands and responses in the initialization routine in the present embodiment.

[2-2. Detailed operation]
The operation when the LV slave device 420 is attached to the LV host device 400 will be described below with reference to FIGS.

  When the power supply is activated, the 1.8V power supply is supplied from the low voltage power supply unit 401 of the LV host device 400 via the low voltage I / F semiconductor chip 402 (host device I / F unit 403) and the power supply line 110. 420. The low voltage I / F semiconductor chip 402 supplies the supplied 1.8V power to all modules arranged in the low voltage I / F semiconductor chip 402 so that each module can be operated. The 1.8 V power supplied to the host device I / F unit 403 is the source of the 1.8 V signal output from the host device I / F unit 403 on the CLK line 111, the CMD line 112, and the DAT line 113. Become.

  On the other hand, the 1.8V power supplied to the LV slave device 420 via the power supply line 110 is supplied to the I / F signal regulator 421 and the BE regulator 426, and is also 1.8V power by the power supply voltage detection unit 422. Detected. Then, the power supply voltage detection unit 422 supplies information indicating that the 1.8V power supply has been received to the I / F control unit 425. The I / F signal regulator 421 of the LV slave device 420 always converts the I / F semiconductor chip 423 (slave device I / F unit 424) into a 1.8V power source regardless of the voltage of the power source supplied through the power line 110. Etc.). Therefore, the 1.8V power supply is always input to the I / F semiconductor chip 423. The I / F semiconductor chip 423 supplies the supplied 1.8 V power to all modules arranged in the I / F semiconductor chip 423 so that each module can be operated. The 1.8V power supplied to the slave device I / F unit 424 is a source of the 1.8V signal of the CMD line 112 and the DAT line 113 output from the slave device I / F unit 424. Further, the BE regulator 426 converts the supplied 1.8V power source into a voltage necessary for the back-end module 427 to drive and supplies the power.

  Similar to the removable system 10 described in FIG. 1, the host device I / F unit 403 of the LV host device 400 has the slave device I / F of the LV slave device 420 through the CLK line 111, the CMD line 112, and the four DAT lines 113. It is connected to the F part 424.

  After power activation, the host device I / F unit 403 generates a 1.8 V signal single-ended clock from the 1.8 V (low voltage) power supplied from the low voltage power supply unit 401, and generates this clock. The data is supplied to the slave device I / F unit 424. Further, for the CMD line 112 and the DAT line 113, the terminal of the host device I / F unit 403 in the output state is set to either the low level (0) or the high level (1) by a pull-up resistor (not shown). When not driven, the state transits to the high level (1) by the 1.8V power supply.

  After the power activation is completed, the host device I / F unit 403 generates an I / F condition check command 501a in the I / F control unit 404. FIG. 6 illustrates the above-described I / F condition check command 501a. The I / F condition check command 501a assigns all or part of the reserved area of the I / F condition check command 201a described in FIG. 3 as an LV check area. The number of bits in the LV check area in this embodiment is 8 bits. The host device I / F unit 403 multiplexes the bit string such that at least one bit is 1 except for 0x00 in the above-described LV check area. The conventional slave device 100 regards the LV check area of the response as a Reserved area and sets 0x00. Therefore, when the host device sets 0x00 in the LV check area of the command, 0x00 is set in the LV check area of the response of the LV slave device or DM slave device described later, and the conventional slave device is installed in the LV host device. It is misjudged that it was done. This is the reason why the host device sets a value other than 0x00 in the LV check area of the command. In the present embodiment, the value of the LV check area is assumed to be 0xA5.

  The I / F condition check command 501a is transmitted to the I / F control unit 425 via the CMD line 112 and the slave device I / F unit 424.

  When receiving information that the power supply voltage detected by the power supply voltage detection unit 422 is 1.8 V, the I / F control unit 425 performs a series of operations described later.

  The I / F control unit 425 interprets the content of the command and generates a corresponding response 501b. In the response 501b of the I / F condition check command 501a, an LV check area having the same number of bits as the LV check area of the I / F condition check command 501a is assigned to the Reserved area of the response 201b described in FIG. 3 (see FIG. 6). ). Then, the I / F control unit 425 multiplexes the same value as the bit string multiplexed in the LV check area of the I / F condition check command 501a, that is, 0xA5 in the LV check area of the response 501b, and returns it to the LV host device 400. To do.

  The I / F control unit 404 of the LV host device 400 performs the first processing when the value of the LV check area multiplexed and transmitted with the I / F condition check command 501a is equal to the value read from the LV check area of the response 501b. Judge that the check was successful. As a result, an initialization command 502a is generated.

  Also in the initialization command 502a, all or part of the Reserved area of the initialization command 202a is assigned as an LV check area, and the number of bits is 8 bits. The value multiplexed in the above LV check area is assigned from 0x00 and excluding the value multiplexed in the LV check area of the I / F condition check command 501a. That is, the value multiplexed in the LV check area of the initialization command 502a is different from the value multiplexed in the LV check area of the I / F condition check command 501a. In this embodiment, it is assumed that 0xB6 is multiplexed. The UHS-I support flag is set to 1.

  The initialization command 502 a generated by the above-described method is transmitted to the I / F control unit 425 via the CMD line 112 and the slave device I / F unit 424.

  The I / F control unit 424 of the LV slave device 420 that has received the initialization command 502a creates a response 502b including at least a UHS-I support flag, an initialization completion flag, and an LV check area. 1 is assigned to the UHS-I support flag, and the value multiplexed in the LV check area of the initialization command 502a, that is, 0xB6 is assigned to the LV check area. In the LV check area of the response 502b, the same number of bits as the LV check area of the initialization command 502a is assigned to the Reserved area of the response 202b described with reference to FIG. 3 (see FIG. 6). The initialization completion flag is assigned 0 or 1 depending on whether the back-end module 427 is being initialized.

  The I / F control unit 425 returns the response 502b created by the above method to the LV host device 400.

  The I / F control unit 404 of the LV host device 400 succeeds in the second check when the value of the LV check area multiplexed and transmitted with the initialization command 502a is equal to the value read from the LV check area of the response 502b. Judge that If a response 502b having an initialization completion flag value of 1 is received within a predetermined time after the initialization command 502a is issued, a voltage switching command as shown in FIG. 2B is issued. Instead, the LV host device 400 can execute a desired operation on the LV slave device 420 by various commands 503a. A communication mode as shown in FIG. 5 is called an LV-UHS-I mode.

[2-3. effect]
According to the first embodiment of the present invention, communication using the CLK line 111, the CMD line 112, and the DAT line 113 by a 1.8V (low voltage) signal can be realized consistently from the time of power-on. . Since the above and the low voltage I / F semiconductor chip 402 of the LV host device 400 are always supplied with 1.8V power, the low voltage I / F semiconductor chip 402 is supplied with 3.3V (high voltage) power. Alternatively, no signal is supplied. Therefore, it is possible to introduce a host device in which the input / output of the I / F semiconductor chip is limited to a low voltage signal of 1.8 V or less while using the same interface as that of the conventional removable system 10. This can contribute to simplification of mounting of the I / F semiconductor chip accompanying the miniaturization of the / F semiconductor chip.

  Further, according to the first embodiment, the determination step is repeated a plurality of times so that the second check is performed after the first check. As a result, it can be more reliably determined that the LV slave device 420 is attached.

Further, according to the first embodiment, the value multiplexed in the LV check area of the initialization command 502a uses a value different from the value multiplexed in the LV check area of the I / F condition check command 501a. Thus, even when the first check based on the value multiplexed in the LV check area of the initialization command 502a is accidentally succeeded due to a malfunction of the slave device, the I / F condition check command 501a By the second check based on a value different from the value multiplexed in the LV check area, it is possible to reduce the possibility of accidental success and more reliably determine that the LV slave device 420 is attached. .
[3. Configuration and Operation of Removable System According to Second Embodiment]
[3-1. Constitution]
FIG. 7 is a block diagram illustrating the configuration of the removable system 30 to which the LV host device 400 and the DM slave device 720 of the present invention are connected. The LV host device 400 is the same as that described with reference to FIG. Further, the DM slave device 720 is derived from the dual mode slave device, and is a slave device that supports any of the non-UHS mode, UHS-I mode, and LV-UHS-I mode.

  The LV host device 400 and the DM slave device 720 are mechanically connected. Further, the LV host device 400 is electrically connected to the DM slave device 720 via the power supply line 110 as in the removable system 10 described with reference to FIG.

  The DM slave device 720 includes an I / F signal regulator 721, a power supply voltage detection unit 722, an I / F semiconductor chip 723, a BE regulator 726, and a back end module 727. The I / F semiconductor chip 723 includes a slave device I / F unit 724 and an I / F control unit 725.

  The host device I / F unit 403 and the slave device I / F unit 724 have a CLK (clock) line 111, a CMD (command) line 112, and a DAT (data) line 113, as in the removable system 10 described in FIG. Signal communication is performed via

[3-2. Detailed operation]
Hereinafter, the operation when the DM slave device 720 is attached to the LV host device 400 will be described with reference to FIG. 7, focusing on the differences from the second embodiment.

  At the time of power activation, a 1.8 V power supply is supplied from the low voltage power supply unit 401 of the LV host device 400 via the low voltage I / F semiconductor chip 402 (host device I / F unit 403) and the power supply line 110 to the DM slave device. 720. The power supplied to the DM slave device 720 via the power supply line 110 is detected by the power supply voltage detection unit 722 as 1.8V power. Information indicating that the 1.8V power supply is detected immediately after the power supply is activated (hereinafter referred to as 1.8V power supply detection information) is notified to the I / F signal regulator 721. At this time, the I / F signal regulator 721 supplies the input 1.8V power as it is to the I / F semiconductor chip 723 (slave device I / F unit 724 and the like). The power supply voltage detection unit 722 also notifies the I / F control unit 725 of 1.8V power supply detection information.

  The I / F control unit 725 that has received the 1.8V power supply detection information controls the DM slave device 720 to operate as an LV slave device. Subsequent operations are the same as those in the second embodiment.

  The 1.8V power supply detection information to the I / F signal regulator 721 is directly notified from the power supply voltage detection unit 722, and once received by the I / F control unit 725, the I / F control unit 725 receives the I / F control unit 725. / F signal regulator 721 may be notified.

[3-3. effect]
According to the second embodiment of the present invention, the DM slave device 720 detects the power supply voltage of the power supply line immediately after startup as a 1.8V power supply. As a result, the DM slave device 720 attached to the LV host device 400 performs the same operation as the LV slave device described with reference to FIG. 4, thereby realizing communication in the LV-UHS-I mode.
[4. Configuration and Operation of Removable System According to Third Embodiment]
[4-1. Constitution]
FIG. 8 is a block diagram illustrating a configuration of a removable system 40 in which the conventional host device 100 and the DM slave device 720 described in the third embodiment are connected. The host device 100 is the same as that described in FIG.

  The host device 100 and the DM slave device 720 are mechanically connected. Further, the host device 100 is electrically connected to the DM slave device 720 via the power supply line 110 as in the removable system 10 described with reference to FIG.

  The host device I / F unit 104 and the slave device I / F unit 724 have a CLK (clock) line 111, a CMD (command) line 112, and a DAT (data) line 113, as in the removable system 10 described in FIG. Signal communication is performed via

[3-2. Detailed operation]
Hereinafter, the operation when the DM slave device 720 is mounted on the host device 100 will be described with reference to FIG. 8, focusing on the differences from the third embodiment.

  At the time of power activation, 3.3 V power is supplied from the power supply unit 101 of the host device 100 to the DM slave device 720 via the I / F signal regulator 102 and the power line 110. The power supplied to the DM slave device 720 via the power supply line 110 is detected by the power supply voltage detection unit 722 as a 3.3V power supply. Information indicating that 3.3V power supply has been detected immediately after power activation (hereinafter referred to as 3.3V power supply detection information) is notified to the I / F signal regulator 721. At this time, the I / F signal regulator 721 supplies the input 3.3V power as it is to the I / F semiconductor chip 723 and the slave device I / F unit 724. The power supply voltage detection unit 722 also notifies the I / F control unit 725 of 3.3V power supply detection information.

  The I / F control unit 725 that has received the 3.3V power supply detection information controls the DM slave device 720 to operate as the conventional slave device 120 thereafter.

  After the power activation is completed, the host device 100 transmits the series of commands illustrated in FIG. 2 to the DM slave device 720. Since the DM slave device 720 is controlled to operate as the slave device 100, the response of the I / F condition check command 201a and the response of the initialization command are 201b and 202b shown in FIG. 2, respectively. This means that 0 is multiplexed to all the bits of the LV check area in 501b and 502b shown in FIG.

  Further, since it is obvious that the DM slave device 720 supports signal communication with a 1.8V signal, when the UHS-I support confirmation bit of the initialization command 202a is set to 1, the response 202b The UHS-I support flag is set to 1. When the I / F control unit 725 receives the voltage switching command 211a issued by the host device 100 that has confirmed the value of the UHS-I support flag, the corresponding response 211b is returned and all of the slave device I / F units 724 are returned. After the terminal is set to the input state, the I / F signal regulator 721 is instructed to change the output from the 3.3V power supply to the 1.8V power supply.

  When the I / F control unit 105 receives the response 211b from the slave device 120, the host device 100 drives all the CLK line 111, the CMD line 112, and the DAT line 113 to the low level (0), and the I / F Instructs the signal regulator 102 to use the output as a 1.8V power supply.

[4-3. effect]
According to the third embodiment of the present invention, the DM slave device 720 detects the power supply voltage of the power supply line immediately after startup as a 3.3V power supply. As a result, the DM slave device 720 attached to the host device 100 can execute the same operation as that of the conventional slave device described with reference to FIG.

Further, as described in the second and third embodiments, the DM slave device 720 of the present invention performs the initialization operation corresponding to the 1.8V power supply when the voltage of the 1.8V power supply is detected. When the voltage of the 3.3V power supply is detected, the initialization operation corresponding to the 3.3V power supply is performed. As a result, the DM slave device 720 of the present invention operates correctly regardless of whether the DM slave device 720 is attached to the conventional host device 100 or the LV host device 400, and becomes a highly compatible device.
[5. Configuration and Operation of Removable System According to Fourth Embodiment]
[5-1. Constitution]
FIG. 9 is a block diagram illustrating the configuration of the removable system 50 in which the LV host device 400 and the UHS-I slave device 920 are connected. The configuration of the UHS-I slave device 920 is the same as that of the conventional slave device 120 described with reference to FIG.

  The LV host device 400 and the UHS-I slave device 920 are mechanically connected. Further, the LV host device 400 is electrically connected to the UHS-I slave device 920 via the power supply line 110, similarly to the removable system 10 described in FIG.

  The host device I / F unit 403 and the slave device I / F unit 123 are the CLK (clock) line 111, the CMD (command) line 112, and the DAT (data) line 113, as in the removable system 10 described in FIG. Signal communication is performed via

  FIG. 10 is a diagram illustrating an initialization routine after the power is turned on when the UHS-I slave device 920 is attached to the LV host device 400.

[5-2. Detailed operation]
Hereinafter, the operation when the UHS-I slave device 920 is attached to the LV host device 400 will be described with reference to FIGS. 9 to 10, focusing on the differences from the embodiments described above.

  At the time of power activation, a 1.8 V power supply is supplied from the low voltage power supply unit 401 of the LV host device 400 via the low voltage I / F semiconductor chip 402 (host device I / F unit 403) and the power supply line 110 to the UHS-I slave. Supplied to the device 920. The 1.8V power supplied to the UHS-I slave device 920 via the power supply line 110 is supplied to the I / F signal regulator 121 and the BE regulator 125.

  The I / F signal regulator 121 of the UHS-I slave device 920 is not originally supposed to input a 1.8V power supply, but it takes extra cost to boost and output to a power supply of 1.8V or higher. The normally input 1.8V power is output as it is and supplied to the I / F semiconductor chip 122 and the slave device I / F unit 123.

  When the LV host device 400 transmits an I / F condition check command 1001a in which 0xA5 is set in the LV check area by a 1.8V signal, the I / F control unit 124 that has received the above transmits the I / F condition check command. The same response 1001b as the response 201b described in FIG. 2 is returned without checking the value of the LV check area of 1001a. Since the power input of the slave device I / F unit 123 is a 1.8V power supply, the response 1001b is transmitted by a 1.8V signal. Therefore, the low voltage I / F control unit semiconductor chip of the LV host device 400 is not destroyed.

  The I / F control unit 404 that has received the response 1001b indicates that the attached slave device does not support the LV-UHS-I mode because the value of the LV check area multiplexed in the response 1001b is 0x00. Judgment is made and the subsequent processing is stopped.

  Since the BE regulator 125 of the conventional UHS-I slave device 920 is designed on the assumption of 3.3V power supply input, the regulator output is likely to be unstable when 1.8V power supply is input. . As a result, the operation of the back-end module 126 becomes indefinite, and it is desirable to stop the operation of the removable system.

[5-3. effect]
According to the fourth embodiment of the present invention, 0x00 is set in the LV check area of the response to the I / F condition check command. Therefore, the LV host device 400 has the attached slave device in the LV-UHS-I mode. Detect that it is not compatible with Since the slave device cannot guarantee normal operation with a 1.8V power supply, the slave device can cause an unexpected operation by stopping the subsequent operation when it is detected that the LV-UHS-I mode is not supported. It can be prevented in advance.
[6. Configuration and Operation of Removable System According to Embodiment 5]
[6-1. Constitution]
FIG. 11 is a block diagram illustrating the configuration of the removable system 60 in which the LV host device 400 and the non-UHS slave device 1120 are connected.

  The non-UHS slave device 1120 includes a high voltage I / F semiconductor chip 1121, a BE regulator 1124, and a back end module 1125. The high voltage I / F semiconductor chip 1121 includes a slave device I / F unit 1122 and an I / F control unit 1123.

  The LV host device 400 and the non-UHS slave device 1120 are mechanically connected. Further, the LV host device 400 is electrically connected to the non-UHS slave device 1120 via the power supply line 110 as in the removable system 10 described with reference to FIG.

  The host device I / F unit 403 and the slave device I / F unit 1122 are the CLK (clock) line 111, the CMD (command) line 112, and the DAT (data) line 113, as in the removable system 10 described in FIG. Signal communication is performed via

  FIG. 12 is a diagram illustrating an initialization routine after power activation when the non-UHS slave device 1120 is attached to the LV host device 400. Unlike the previous embodiments, there are at least three patterns.

[6-2. Detailed operation]
Hereinafter, the operation when the non-UHS slave device 1120 is attached to the LV host device 400 will be described with reference to FIGS. 11 to 12, focusing on the differences from the above-described embodiments.

  The non-UHS slave device 1120 is supplied with 1.8V power from the LV host device 400 via the power supply line 110. A slave device that is a constituent element of the high voltage I / F signal regulator semiconductor chip 1121 when a 1.8 V power supply is input to the high voltage I / F signal regulator semiconductor chip 1121 originally designed on the assumption of a 3.3 V power supply input. There is a high possibility that the I / F unit 1122 and the I / F control unit 1123 do not operate normally.

  Pattern (a) is a case where the slave device I / F unit 1122 or the I / F control unit 1123 cannot correctly recognize the I / F condition check command 1201a and cannot return a response. At this time, the LV host device 400 determines that the response has not been received even after a predetermined time has elapsed after the I / F condition check command 1201a is issued.

  Pattern (b) is a case where the high voltage I / F signal regulator semiconductor chip 1121 accidentally operates correctly even with 1.8V power input. At this time, 0x00 is set in the LV check area of the response 1211b generated by the I / F control unit 1123 that correctly recognizes the I / F condition check command 1211a and is transmitted to the LV host device 400.

  At this time, the LV host device 400 stops the subsequent processing as in FIG. 10 of the fourth embodiment.

  In pattern (c), although the I / F condition check command 1221a is received and recognized correctly, the operation of the high voltage I / F signal regulator semiconductor chip 1121 is unstable, so the LV check of the I / F condition check command 1221a is performed. This is a case where the same value as the value set in the area is accidentally multiplexed in the LV check area of the response 1121b and returned to the LV host device 400.

  At this time, the I / F control unit 404 determines that the first check has succeeded, and subsequently sets a value different from the value set in the I / F condition check command 1221a in the LV check area of the initialization command 1222a. Then send.

  The non-UHS slave device 1120 sets and returns the same value as the response 1221b in the LV check area of the response 1222b of the initialization command 1222a.

  Thereby, the I / F control unit 404 determines that the second check has failed, and stops the subsequent processing.

[6-3. effect]
According to the fifth embodiment of the present invention, the operation of the I / F semiconductor chip is unstable due to insufficient supply power voltage by setting bit strings having different values in the LV check area of at least two commands. However, it can be finally determined that the process is to be stopped. As in the fourth embodiment, the slave device cannot guarantee normal operation with a 1.8 V power supply, and therefore, when it is detected that the LV-UHS-I mode is not supported, the subsequent operation is stopped. It is possible to prevent the slave device from executing an unexpected operation.
[7. Configuration and Operation of Removable System According to Embodiment 6]
[7-1. Constitution]
FIG. 13 is a block diagram illustrating a configuration of a removable system 70 in which a conventional host device 100 and an LV slave device 420 are connected.

  The host device 100 and the LV slave device 420 are mechanically connected. In addition, the host device 100 is electrically connected to the LV slave device 420 via the power supply line 110 as in the removable system 10 described with reference to FIG.

  The host device I / F unit 104 and the slave device I / F unit 424 have a CLK (clock) line 111, a CMD (command) line 112, and a DAT (data) line 113, as in the removable system 10 described in FIG. Signal communication is performed via

  FIG. 14 is a diagram illustrating an initialization routine after power activation when the LV slave device 420 is mounted on the host device 100.

[7-2. Detailed operation]
The operation when the LV slave device 420 is attached to the LV host device 400 will be described below with reference to FIGS.

  At the time of power activation, 3.3 V power is supplied from the power supply unit 101 of the host device 100 to the LV slave device 420 via the I / F semiconductor chip 103 (host device I / F unit 104) and the power line 110. . The 3.3V power supplied to the LV slave device 420 via the power line 110 is supplied to the I / F signal regulator 421 and the BE regulator 426, and is detected by the power supply voltage detection unit 422 as 3.3V power. Is done. Then, the power supply voltage detection unit 422 supplies information indicating that the 3.3V power supply has been received to the I / F control unit 425.

  The BE regulator 426 of the LV slave device 420 is designed on the assumption of a 1.8V power input. Therefore, there is no guarantee that the back-end module 427 operates correctly when 3.3V power is input.

  Therefore, when the I / F control unit 425 detects that the power supplied via the power supply line 110 is a 3.3V power supply, the I / F control unit 425 performs control so as not to return a response to the input command.

  Therefore, when the host apparatus 100 transmits the I / F condition check command 1401a, the I / F control unit 425 that has received the above does not return a corresponding response (FIG. 14A). Since the I / F condition check command 1401a transmitted from the host device 100 is transmitted by a 3.3V signal, the I / F semiconductor chip 423 of the LV slave device 420 needs to have a withstand voltage performance of 3.3V input. There is.

  As a result, since the host device 100 cannot receive a response even after a predetermined time has elapsed after issuing the I / F condition check command 1401a, the host device 100 determines that an error has occurred and stops the subsequent processing.

  Note that some conventional host devices 100 issue an initialization command 1411a without issuing an I / F condition check command 1401a after power-up, as shown in FIG. 14B. In this case, the LV slave device 420 always returns a response in which the initialization completion flag is set to 0 with respect to the received initialization completion flag. In the example of FIG. 14B, the initialization completion flag is set to 0 for both responses 1411b and 1412b corresponding to the initialization commands 1411a and 1412a.

  If the host apparatus 100 cannot receive a response in which the initialization completion flag is set to 1 for a predetermined period (timeout period) after the first initialization command 1411a is issued, the host apparatus 100 gives up initialization and stops the subsequent processing. As a result, the same result can be obtained for a host device that does not issue the I / F condition check command 1401a.

[7-3. effect]
According to the sixth embodiment of the present invention, the LV slave device detects the voltage of the supplied power supply,
If it is 3.3 V (high voltage), a response corresponding to the received command is not returned. In this embodiment, since it is not possible to guarantee that the slave device operates normally, it is possible to prevent the slave device from executing an unexpected operation by stopping the subsequent operation.

Further, by providing the slave device I / F unit 424 of the LV slave device with a withstand voltage of 3.3V signal input, even if the LV slave device is mounted on a conventional host device, it is not destroyed.
[8. Addendum]
In the present disclosure, the host device includes a total of two types including the LV host device 400 in addition to the conventional host device 100, and the slave device includes the LV slave device 420 and the DM slave device 720 in addition to the conventional slave device 120. There are a total of three types. The operation of each host device and slave device combination (2 × 3 = 6 types) has been described. Among these, the combination of the conventional host device 100 and the LV slave device 420 and the combination of the LV host device 400 and the conventional slave device 120 are inoperable, but the host device or the slave device is destroyed. No fatal problem occurs. It was confirmed that the combinations other than the above operate normally.

  In embodiments of the present invention, it is possible to define multiple low voltage signals or power supplies. For example, in FIG. 7, when the LV host device 400 and the DM slave device 720 support 1.8V and 1.2V signal voltages, the LV host device 400 supplies 1.8V power to the DM slave device 720. The LV-UHS-I mode is completed until initialization. Thereafter, the signal voltage can be changed from 1.8 V to 1.2 V by using a voltage switching command in the UHS-I mode.

  In the embodiment of the present invention, the high voltage signal or power supply voltage is 3.3 V, and the low voltage signal or power supply voltage is 1.8 V. However, if the magnitude relationship of the voltages is maintained, Other voltage values may be used. In general, when the withstand voltage of the low voltage I / F semiconductor chip 402 mounted on the LV host device 400 is x (V), the LV host device 400 supplies power of x (V) or less via the power line. The low voltage I / F semiconductor chip 402 is not destroyed by the input of the high voltage signal.

  In the first to fourth embodiments, the value of the LV check area is confirmed twice by the I / F condition check command and the initialization command. Either the first I / F condition check command or the initialization command is used. You may carry out only by one side. The initialization command can be issued any number of times until the process proceeds to the next process during initialization and after completion of initialization. Therefore, the value of the LV check area may be confirmed only with the initial initialization command or with any or all of the initialization commands.

  In all of the embodiments, the I / F condition check command and its response, and the initialization command and its response have an LV check area of 8 bits, but the present invention is implemented if it is 1 bit or more. Is possible. As the number of bits increases, as shown in FIG. 12C, the value set in the LV check area of the response becomes accidentally different from the value in the LV check area multiplexed in the command due to the malfunction of the slave device. The probability of matching is reduced, and more accurate judgment can be made.

  Further, in the LV check area, the command and the response corresponding to the command need only have the same number of bits, and different commands or responses may have different numbers of bits. For example, as shown in FIG. 15A, the LV check area of the I / F condition check command and its response may be 8 bits, and the LV check area of the initialization command and its response may be 4 bits.

  Further, as shown in FIG. 15B, the LV check area does not necessarily have to be continuous as long as it is within the reserved area of the conventional command or packet.

  In addition, the LV slave device or DM slave device of the present invention sets the same value as the value of the LV check area multiplexed in the command received from the host apparatus in the LV check area of the corresponding response to the host apparatus. Replied. In addition to this, the slave device sets a value obtained by performing a predetermined conversion on the value of the received LV check region in the LV check region of the response, and the host device that has received the above changes the value of the received LV check region to the value of the LV check region. It is also possible to perform a reverse conversion of a predetermined conversion and compare it with the value of the LV check area transmitted by the host device.

  FIG. 16 shows that the slave device of the present invention (LV slave device or DM slave device, referred to herein as the slave device for the sake of simplicity) is received from the host device of the present invention (referred to herein as the host device for the sake of simplicity). Example of returning a value obtained by performing a conversion of inverting the bit string of the selected LV check area (changing 0 to 1 and changing 1 to 0 for all bits of the bit string) as the value of the LV check area of the response It is.

  Specifically, when the slave device receives the I / F condition check command 1601a, the value 0xA5 of the LV check area multiplexed in the command is read. Then, 0x5A obtained by inverting 0xA5 is set in the LV check area of the response 1601b and transmitted to the host device. The host apparatus that has received the response 1601b reads the value of the LV check area multiplexed in the LV check area, and performs the inverse conversion of the above conversion (in this example, inversion of the bit string) to obtain 0xA5. Since this value is equal to the value of the LV check area set by the host device in the I / F condition check command 1601a, the first check by the I / F condition check command 1601a is successful.

  Similarly, a value 0x49 obtained by performing bit inversion conversion on the value 0xB6 of the LV check area multiplexed in the initialization command 1602a is set in the LV check area of the response 1602b. Then, the host device obtains a value 0xB6 obtained by performing inverse transformation on the value 0x49 of the LV check area multiplexed in the response 1602b, and detects that the host apparatus is equal to the value of the LV check area set in the initialization command 1602a. By doing so, it is determined that the second check is successful.

  When using bit string inversion, the host device must not set 0xFF in the LV check area of the command. This is because the value of the LV check area multiplexed in the response from the LV slave device or the DM slave device is 0x00, so that it cannot be distinguished from the conventional slave device.

  The present disclosure can be applied to a host device, a slave device, an interface semiconductor device, and a removable system.

10 to 70 Removable System 100 Host Device 101 Power Supply Unit 102 I / F Signal Regulator 103 I / F Semiconductor Chip 104 Host Device I / F Unit 105 I / F Control Unit 110 Power Line 111 CLK Line 112 CMD Line 113 DAT Line 120 Slave device 121 I / F signal regulator 122 I / F semiconductor chip 123 Slave device I / F unit 124 I / F control unit 125 BE regulator 126 Back-end module 201a I / F condition check command 201b 201a response 202a Initialization command 202b 202a response 203a Various commands 203b 203a response 211a Voltage switching command 211b 211a response 400 LV host device 401 Low Voltage power supply unit 402 Low voltage I / F semiconductor chip 403 Host device I / F unit 404 I / F control unit 420 Slave device 421 I / F signal regulator 422 Power supply voltage detection unit 423 I / F semiconductor chip 424 Slave device I / F unit 425 I / F control unit 426 BE regulator 427 Backend module 501a I / F condition check command 501b 501a response 502a Initialization command 502b 502a response 503a Various commands 503b 503a response 720 DM slave device 721 I / F signal Regulator 722 Power supply voltage detection unit 723 I / F semiconductor chip 724 Slave device I / F unit 725 I / F control unit 726 BE regulator 727 Back end module 920 UHS- I slave device 1001a I / F condition check command 1001b Response of 1001a 1120 UHS-I slave device 1121 High voltage I / F semiconductor chip 1122 Slave device I / F unit 1123 I / F control unit 1124 BE regulator 1125 Backend module 1201a I / F condition check command 1211a I / F condition check command 1211b 1211a response 1221a I / F condition check command 1221b 1221a response 1222a Initialization command 1222b 1222a response 1401a I / F condition check command 1411a I / F condition check command 1411b Response 1411a 1412a Initialization command 1412b Response 1414a 16 Response of response 1602a I / F conditions check command 1602b 1602a of 1a I / F conditions check command 1601b 1601a

Claims (3)

An interface unit mechanically connectable to both the first slave device corresponding to the first interface voltage and the second slave device corresponding to the second interface voltage lower than the first interface voltage; ,
After notifying a request signal to the slave device mounted on the interface unit, the response signal notified from the slave device in response to the request signal is a response signal from the second slave device. If determined, the initialization operation by the second interface voltage is continued, while the response signal notified from the slave device in response to the request signal is not a response signal from the second slave device. And a control unit that regulates the initialization operation when it is determined.   The host device according to claim 1, wherein the interface unit cannot be logically connected to the first slave device, but can be logically connected to the second slave device. A removable system formed of a host device and a slave device detachably attached to the host device,
The host device is
An interface unit mechanically connectable to both the first slave device corresponding to the first interface voltage and the second slave device corresponding to the second interface voltage lower than the first interface voltage; ,
After notifying a request signal to the slave device mounted on the interface unit, the response signal notified from the slave device in response to the request signal is a response signal from the second slave device. If determined, the initialization operation by the second interface voltage is continued, while the response signal notified from the slave device in response to the request signal is not a response signal from the second slave device. And a controller that restricts the initialization operation when it is determined.